* FTSE 100 touches 21-mth high
* Commods firm as oil, metal prices rise
* Banks higher helped by Fed rate comments
By Jon Hopkins
LONDON, 17 March (Reuters) - Britain's top share index gained 0.4 percent around midday on Wednesday, lifted by strength in commodity issues and banks as investors welcomed the Federal Reserve's pledge to hold interest rates near zero.
By 1153 GMT, the FTSE 100 <
> index was up 22.21 points at 5,642.64, just off an intraday 21-month peak of 5,657.70, after the U.S. central bank held benchmark rates near zero and maintained its pledge to keep them low for an extended period."Yesterday's news from the Fed has bolstered the move of cash back into risk assets, mainly banks and commodity issues, despite the strong recent rally," said Mic Mills, senior trader at ETX Capital.
"But although a new multi-month peak has been hit by the FTSE, investors remain wary of what could be around the corner, particularly given the looming UK election," Mills added.
Commodity stocks added the most points to the FTSE 100 index as metal prices firmed and crude prices <CLc1> pushed past $82 a barrel helped by a softer dollar following the Fed comments.
Miners were the top blue-chip gainers, with Fresnillo <FRES.L>, Kazakhmys <KAZ.L>, Xstrata <XTA.L>, Vedanta Resources <VED.L>, and Lonmin <LMI.L> up 1.6 to 2.7 percent.
Rio Tinto added 2.5 percent. China's top state-owned nonferrous metals company Chinalco confirmed it is in talks with Rio Tinto about potential joint ventures in Mongolia and Guinea, a Chinese newspaper said on Wednesday. [
]Oil majors also saw good gains, with BP <BP.L>, BG Group <BG.L>, Royal Dutch Shell <RDSa.L>, Tullow Oil <TLW.L>, and Cairn Energy <CNE.L> adding 0.2 to 1.5 percent.
Banks were in demand helped by the Fed's pledge and by Tuesday's reassuring news on Greece's debt problems, which saw EU finance ministers pledge support if needed and agency S&P affirm its debt rating on the country.
Lloyds Banking Group <LLOY.L>, Royal Bank of Scotland <RBS.L>, Barclays <BARC.L> and Standard Chartered <STAN.L> gained 0.4 to 1.6 percent, while HSBC <HSBA.L>, which traded ex-dividend on Wednesday, added 0.4 percent.
KINGFISHER SOARS
Among individual movers, DIY retailer Kingfisher <KGF.L> added 2.8 percent as HSBC raised its rating to "overweight", citing improved visibility on long-term cash flow.
Elsewhere on the high street, however, Marks & Spencer <MKS.L> fell 1.3 percent as JP Morgan cut its rating to "underweight" from "neutral", noting forecast risks and strategic questions.
Drugs firm Shire <SHP.L> was also blighted by a broker downgrade, off 1.6 percent as Citigroup cut its stance to "sell" from "buy" on valuation grounds.
Elsewhere, hedge fund manager Man Group fell 3.1 percent as Numis cut its rating to "add" from "buy" and Morgan Stanley reduced its target price for the firm to 260 pence from 340 pence.
Security services group G4S <GFS.L> was the biggest FTSE 100 faller, down 4.5 percent after falls on Tuesday following in-line results, with traders noting talk that top shareholder Skagen Trust was selling 141 million shares, or around 10 percent of the firm. [
]Ex-dividend factors took 6.14 points off the FTSE 100 index with Inmarsat <ISA.L>, Standard Life <SL.L>, Thomas Cook Group <TCG.L> and WPP Group <WPP.L> also losing their dividend rights.
On the second line, transport issues got a boost after Arriva <ARI.L> confirmed it had recieved an unsolicited bid approach after takeover rumours on Tuesday.
Newspaper reports on Wednesday suggested German state-owned rail operator Deutsche Bahn was the likely predator.
Arriva was the top FTSE 250 <
> riser, up 18.9 percent, while peers FirstGroup <FGP.L>, National Express <NEX.L>, and Stagecoach <SGC.L> took on 3.5 to 4.2 percent.Equities showed little reaction but sterling rose, nearing a 3-month high versus the dollar after UK employment data came in better than expected. [
]Also boosting the pound were Bank of England minutes showing policymakers voted unanimously to to keep monetary policy unchanged this month, with some pointing to an increase in upside inflation risks. [
](Editing by Simon Jessop)